Long-term contracts (Collaborative Research and Development Agreement Narrative) (Details) (USD $)	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012
Long-Term Contracts Collaborative Research And Development Agreement Narrative Details
Date of collaborative research and development agreement	March 2013
Amount of collaborative research and development agreement	$ 4,600,000
Development revenue	$ 2,909,000	$ 0

Revenues from the sale of other goods or rendering of other services, not elsewhere specified in the taxonomy; net of (reduced by) sales adjustments, returns, allowances, and discounts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(a),(d))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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